1. Field of the Invention
The present invention relates to a manufacturing method of a light emitting device, and more particularly, to a manufacturing method of a side view type light emitting device.
2. Description of the Related Art
In JP-A-2009-177093, JP-A-2009-302527, JP-A-2007-027801. JP-A-2007-027800, JP-A-2006-108333, JP-A-2006-054410 and JP-A-2004-363503, there are disclosed side view type light emitting devices (edge type light emitting devices).
JP-A-2009-177093 discloses that, in order to facilitate die-cutting at the time of injection molding of a package body of the light emitting device, the package body includes a box-shaped block part of a front side and an inclined block part of a back side, an upper surface and a lower surface of the box-shaped block part are approximately in parallel with each other and an upper surface and a lower surface of the inclined block part form tapered surfaces inclined to be narrowed toward the back side.
JP-A-2009-177093 discloses that an injection molding mold for injection-molding the package body includes a fixed mold member and a movable mold member, the fixed mold member forms the inclined block part, and the movable mold member forms the box-shaped block part.
Moreover, JP-A-2009-177093 discloses that a protrusion part s formed at a lower side of the inclined block part so as to be linked with the back, and serves as a support when the package body is placed, so that the slope of the package body is suppressed.
As illustrated in FIG. 17, a package body 101 of a side view type light emitting device 100 in the related art includes a box-shaped block part 102 on a front side and an inclined block part 103 on a back side, an upper surface and a lower surface of the box-shaped block part 102 are approximately in parallel with each other and an upper surface and a lower surface of the inclined block part 103 respectively form tapered surfaces 103a and 103b inclined to be narrowed toward the back side.
At a boundary line between the box-shaped block part 102 and the inclined block part 103, a stepped portion SP is formed such that the box-shaped block part 102 is slightly larger than the inclined block part 103.
The stepped portion SP is provided in order to absorb an alignment error between a fixed mold member and a movable mold member of the injection molding mold for injection-molding the package body 101.
From both side surfaces of the inclined block part 103, terminal parts 104 of lead frames, which are external connection terminals of the light emitting device 100, protrude.
As illustrated in FIG. 18A, since the upper surface of the inclined block part 103 is the tapered surface 103a and the stepped portion SP is formed at each of the parts 102 and 103, when the upper surface side of the package body 101 of the light emitting device 100 is sucked and conveyed by a suction collet BC, the suction collet BC may suck the upper surface side in the state of covering the stepped portion SP by a variation of the suction position.
Then, since the suction force of the suction collet BC is not reliably applied to the package body 101 and the package body 101 becomes unstable, there is a problem that the package body 101 is easily detached from the suction collet BC.
As illustrated in FIG. 18B, there is a problem that the package body 101 is conveyed in an inclined state and is placed on a wiring board MS, and the terminal part 104 of the lead frame is surface-mounted on the wiring board MS by solder SD in the state in which the package body 101 has been inclined.
When the package body 101 is surface-mounted on the wiring board MS in the inclined state, since a light emitting direction a from the front side of the light emitting device 100 is also inclined downward, it is not possible to allow the light emitting direction a to be a direction being parallel with the wiring board MS, which is a correct direction.
For example, when the light emitting device 100 is used as a back light of a liquid crystal display, if the light emitting direction a for a liquid crystal panel is not correct, it causes color irregularity in the liquid crystal panel.
When the stepped portion SP is not provided at the parts 102 and 103 of the package body 101, if positional shift occurs in the boundary line of the parts 102 and 103 by the alignment error of the injection molding mold, the inclined block part 103 protrudes from the box-shaped block part 102 and an external dimension of the package body 101 is not within a standard, resulting in a problem that yield is reduced.
Furthermore, when the upper surface and the lower surface of the inclined block part 103 are not allowed to form the tapered surfaces 103a and 103b and are allowed to be approximately parallel with each other similarly to the box-shaped block part 102, the release property (the easiness of die-cutting) of the fixed mold member is deteriorated, resulting in a problem that productivity is reduced.
Accordingly, providing the stepped portion SP at the parts 102 and 103 of the package body 101 and allowing the upper surface and the lower surface of the inclined block part 103 to form the tapered surfaces 103a and 103b are essential to the side view type light emitting device 100 because the yield and the productivity are not impaired.
Although not disclosed in the specification of JP-A-2009-302527, drawings illustrate a stepped portion corresponding to the stepped portion SP.
In JP-A-2007-027801, JP-A-2007-027800, JP-A-2006-108333, JP-A-2006-054410, and JP-A-2004-363503, there are not disclosed configurations corresponding to the stepped portion SP and the tapered surfaces 103a and 103h. However, as described above, since the stepped portion SP and the tapered surfaces 103a and 103b are essential, when the technologies disclosed in JP-A-2007-027801. JP-A-2007-027800, JP-A-2006-108333, JP-A-2006-054410, and JR-A-2004-363503 are actually used for developing a product, configurations corresponding to the stepped portion SP and the tapered surfaces 103a and 103b need to be essentially provided.
Accordingly, also in JP-A-2009-177093, JP-A-2009-302527, JP-A-2007-027801, JP-A-2007-027800, JP-A-2006-108333, JP-A-2006-054410, and JP-A-2004-363503, the aforementioned problems occur.